Internal carotid artery stenting for intracranial atherosclerosis

Intracranial Atherosclerosis Increases the Risk of Postoperative Stroke After Cardiac Surgery: A Review and Meta-Analysis

BACKGROUND

Postoperative stroke is a devastating complication of cardiac surgery with high morbidity, mortality, and health care cost. Extracranial carotid atherosclerosis (ECAS) is a known risk factor for stroke; however, the impact of intracranial atherosclerosis (ICAS) remains unclear. To our knowledge, this is the first literature review of ICAS in cardiac surgery. We aimed to assess the prevalence, association with postoperative stroke, and perioperative management of ICAS in cardiac surgery.

METHOD

A search was performed to identify studies reporting rates of ICAS and stroke after cardiac surgery. Data extraction and primary outcomes for meta-analysis included the prevalence of preoperative ICAS and the association between ICAS and stroke. Risk ratios (RRs) and 95% confidence intervals (CIs) were pooled by random-effects modelling.

RESULTS

Seventeen studies were reviewed and seven were included in the meta-analysis, comprising 4,936 patients. Prevalence of intracranial atherosclerosis (ICAS) among cardiac surgery patients was 21% (95% CI 13%-32%). Patients with ICAS were more likely to develop postoperative stroke (RR 3.61; 95% CI 2.30-5.67; p<0.001). ICAS was more closely associated with stroke than ECAS. Preoperative brain perfusion single-photon emission computed tomography with acetazolamide challenge, staged intracerebral revascularisation, or conversion to off-pump coronary artery bypass grafting are described management options for ICAS.

CONCLUSION

Patients with ICAS are 3.61 times more likely to develop stroke after cardiac surgery. Known predictors for ICAS can be used to develop risk stratification screening tools. Further research with diverse cohorts is required to develop evidence-based guidelines for screening and management of ICAS in cardiac surgery.

Comprehensive investigation of RNF213 nonsynonymous variants associated with intracranial artery stenosis

Intracranial artery stenosis (ICAS) is the most common cause of ischemic stroke worldwide. RNF213 single nucleotide variant c.14429G > A (p.Arg4810Lys, rs112735431) was recently reported to be associated with ICAS in East Asians. However, the disease susceptibility of other RNF213 variants has not been clarified. This study comprehensively investigated ICAS-associated RNF213 variants in a pool of 168 Japanese ICAS patients and 1,194 control subjects. We found 138 nonsynonymous germline variants by target resequencing of all coding exons in RNF213. Association study between ICAS patients and control subjects revealed that only p.Arg4810Lys had significant association with ICAS (P = 1.5 × 10^-28, odds ratio = 29.3, 95% confidence interval 15.31-56.2 [dominant model]). Fourteen of 138 variants were rare variants detected in ICAS patients not harboring p.Arg4810Lys variant. Two of these rare variants (p.Cys118Arg and p.Leu2356Phe) consistent with variants previously reported in moyamoya disease patients characterized by stenosis of intracranial artery and association with RNF213, and three rare variants (p.Ser193Gly, p.Val1817Leu, and p.Asp3329Tyr) were found neither in control subjects and Single Nucleotide Polymorphism Database. The present findings may improve our understanding of the genetic background of intracranial artery stenosis.

Intracranial atherosclerotic disease

Intracranial atherosclerosis (ICAS) is a progressive pathological process that causes progressive stenosis and cerebral hypoperfusion and is a major cause of stroke occurrence and recurrence around the world. Multiple factors contribute to the development of ICAS. Angiography imaging techniques can improve the diagnosis of and the selection of appropriate treatment regimens for ICAS. Neither aggressive medication nor endovascular interventions can eradicate stroke recurrence in patients with ICAS. Non-pharmacological therapies such as remote ischemic conditioning and hypothermia are emerging. Comprehensive therapy with medication in combination with endovascular intervention and/or non-pharmacological treatment may be a potential strategy for ICAS treatment in the future. We summarized the epidemiology, pathophysiological mechanisms, risk factors, biomarkers, imaging and management of ICAS.